I. Field of the Invention
The present invention relates to a method of operating a ladle refining furnace in which a ladle is covered by a water-cooled cover, and Ar gas is blown into molten steel inside the ladle through bubbling lances so as to stir the molten steel.
II. Description of the Prior Art
In a ladle refining furnace which has bubbling lances submerged in molten steel, when a part of an Ar gas outlet port is damaged, the iron lumps attach to the melted portion, thus clogging the lances. When such clogging occurs, Ar gas cannot be easily blown, and the operation may have to be stopped temporarily.
According to the studies made by the present inventors, it was confirmed that attachment of the iron lumps is frequently caused when the lances are inserted into molten steel, the lances are withdrawn, and the Ar gas flow rate is decreased.